Water ski



W. R. BLAKE Nov. 6, 1962 WATER SKI W/Y/l'dfn R. Blake 1N VEN TOR.

United States Patent f 3,061,846 WATER SKI William R. Blake, 907 EastAve., Baxter Springs, Kans. Filed Aug. 5, 1959, Ser. No. 831,799 4Claims. (Cl. 9-310) This invention relates to water skis and moreparticularly to a reinforced plastic water ski.

An object of the invention is to provide a water ski of unique design.Briefly, the prow or nose of the ski incorporates a reflex curve upwardfrom the planing surface and at an elevation where other ski designsterminate. The design in accordance with this invention recurves and thebody of the ski projects forward and upward at approximately a 10 angle,although the angularity may be varied within practical limits.Accordingly, there is a very important inflection area at the place inthe reflex curvature where the curvature changes from concave to convex.

The contours of this section of the prow are flared, for instance, likethe prow section of some boats. This flaring provides a laterallystabilizing effect on the forward part of the ski, tending to hold thedirection of the ski in a constant path when the user is proceedingthrough waves, wakes or other rough water.

Further, the reflex curve, when viewed as a profile, tends to providelaminar water flow over the top of the prow in moments of unavoidablesubmersion, for instance through wakes, etc., in contrast to a turbulentvortex-type flow which exists in previous designs where the nose merelysweeps up along a radius and terminates on this radius. Laminar flowover the ski top theoretically is more conductive to maximum lift thanturbulent flow, and swamping is considerably less likely.

Accordingly, a further object of the invention is to provide a ski whichis hydrodynamically more stable than previous skis and which providesfor considerably more enjoyment in the use thereof.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawing forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a top view of the ski constructed in accordance with theinvention;

FIGURE 2 is a side view of the ski in FIGURE 1;

FIGURE 3 is a bottom view of the ski in FIGURE 1;

FIGURE 4 is a front view of the ski;

FIGURE 5 is a rear elevational view of the ski; and

FIGURE 6 is an enlarged sectional view taken substantially on the line6-6 of FIGURE 2.

In the accompanying drawings there is illustrated a ski 10 whichexemplifies the principles of the invention. This ski has a body 12 madeof plastic, although the principles of the invention can be practiced inconnection with skis of other construction. Mentioned as a preference,the flotation core or body provides beam strength and rigidity byadopting a plastic laminate sandwich construction with the core and skinof reinforced plastic integrally molded into a one-piece construction.

Foot receiving device 14 is shown in dotted lines in FIGURE 1 and thisis conventional. There is a depression 16 in body 12 aft of the footreceiving device, and a stabilizing fin 18 located on the longitudinalaxis of the body and depending downwardly from the bottom of depression16. This fin is short in comparison with the length of the ski body andfunctions as a keel.

Prow 20 has a tapered tip when viewed in plan, and the prowconfiguration is most important. It is a wave breaker prow in contrastto other ski designs. The prow ice is symmetrical about a longitudinalaxis of the ski body and has a lower reflex curve surface 22 at theforward end of the longitudinal center line. The curvature 34 is convexdownward and is in the direction upward from the planing surface 26. Ator near an elevation where other designs terminate the curvature of thenew design passes through an inflection area 32 recurving and becomingconcave downward. The forward end of the prow 20 projects forward andupward at an angle of approximately 10 degrees (FIG. 2) measured from ahorizontal plane. The recurved area 22 terminates in the leading edge 33of the ski body.

The side contours of this section of the prow are dished inward andflared, there being flared surfaces 28 and 30 (FIG. 6) commencing at theforward tip of the prow on opposite sides of the upward curvature andterminating forward of the rear end of the reflex curvature. The flaredsurfaces 28 and 30 are upwardly and outwardly flared and provide alateral stabilizing effect on the forward part of the ski tending tohold the direction of the ski in a constant path when the user proceedsthrough waves, wakes and other disturbances.

As shown best in FIGURE 2 and in FIGURE 4 there is an inflection area 32between the forward section of the convex downward curvature 34 and therear section of the re-curved (concave downward) curvature 22. Thisinflection area 32 may be smoothly faired, or abruptly stepped asillustrated in FIGURE 2 to further assist in providing maximum lift. Theuse and operation of the ski has been previously discussed. Accordingly,further description is unnecessary.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. A water ski comprising a ski body, said ski body having a lowerplaning surface and a prow, said prow curving smoothly forwardly andupwardly and including a lower reflex curvature surface from the tipthereof and merging into said planing surface, said prow being taperedin plan and toward the tip thereof, said prow also having laterallyspaced upwardly and outwardly flared opposite side marginal portionsextending from the region of the tip rearwardly of the ski body andforming upwardly and outwardly curving concave lower surfaces providinglateral stability on the forward part of the ski.

2. A water ski comprising a ski body, said ski body having a lowerplaning surface and a prow, said prow curving smoothly forwardly andupwardly and including a lower reflex curvature surface from the tipthereof and merging into said planing surface, said prow being taperedin plan and toward the tip thereof, said prow also having laterallyspaced upwardly and outwardly flared opposite side marginal portionsextending from the region of the tip rearwardly of the ski body andforming upwardly and outwardly curving concave lower surfaces providinglateral stability on the forward part of the ski, an inflection area insaid reflex curvature surface and at approximately the line of divisionbetween the forward portion and the rear portion of said reflexcurvature surface.

3. A water ski comprising a ski body, said ski body having a lowerplaning surface and a prow, said prow curving smoothly forwardly andupwardly and including a lower reflex curvature surface from the tipthereof and merging into said planing surface, said prow being taperedin plan and toward the tip thereof, said prow also having laterallyspaced upwardly and outwardly flared opposite side marginal portionsextending from the region of the tip rearwardly of the ski body andforming upwardly and outwardly curving concave lower surfaces providinglateral stability on the forward part of the ski, an inflection area insaid reflex curvature surface and at approximately the line of divisionbetween the forward portion and the rear portion of said reflexcurvature surface, a keel at the aft part of said ski body, and meansconnected with the ski body by which to receive the foot of a person.

4. A ski restricted exclusively for use on water, said ski comprising aski body having a lower planing surface and a prow, said prow curvingsmoothly forward and upwardly and incorporating a reflex curvature atthe bottom thereof and an inflection area in said reflex curvature, saidprow also having transversely spaced upwardly and outwardly flaredopposite side marginal portions on 4 each side of the longitudinalcenter line of the ski body and commencing in the region of the tip ofthe prow and forming outwardly curving concave lower surfacesterminating at a place between the forward and rear ends of the reflexcurvature.

References Cited in the file of this patent UNITED STATES PATENTS2,126,152 Suits Aug. 9, 1938 2,374,229 Newham Apr. 24, 1945 2,382,150Hartman Aug. 14, 1945 2,866,210 Romig Dec. 30, 1958 2,915,031 JohnstonDec. 1, 1959 2,940,409 Chaffee June 14, 1960 FOREIGN PATENTS 212,221Switzerland Feb. 3, 1941

